Answer:
Actually, it’s not the DNA itself cannot leave the nucleus, but the Chromosome or Chromatin. Because, in the nucleus, DNAs are folded into Chromatin or Chromosome. Chromatin or Chromosome just like a rope, and the DNA just the fiber. It’s the rope cannot escape from the nucleus instead of the fibers.
Explanation:
In this example I used blue and brown eyes. Brown eyes are a dominant trait and are represented by a big B while blue eyes are recessive and represented by a little b. If an offspring gets a B from the father and a b from the mother the offspring will have brown eyes.
Hope this helps!!
usually when there's a mutation the genetic material is either deleted, substituted, and instertion of DNA